[AiS] Fix ownership issue for image service observers

chrome/browser/bitmap_fetcher/bitmap_fetcher_service.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/bitmap_fetcher/bitmap_fetcher_service.h"
 
 #include "base/memory/weak_ptr.h"
 #include "chrome/browser/bitmap_fetcher/bitmap_fetcher.h"
 #include "chrome/browser/profiles/profile.h"
 #include "net/base/load_flags.h"
@@ skipping 27 matching lines @@
   DISALLOW_COPY_AND_ASSIGN(BitmapFetcherRequest);
 };
 
 BitmapFetcherRequest::BitmapFetcherRequest(
     BitmapFetcherService::RequestId request_id,
     BitmapFetcherService::Observer* observer)
     : request_id_(request_id), observer_(observer) {
 }
 
 BitmapFetcherRequest::~BitmapFetcherRequest() {
-  SkBitmap empty_bitmap;
-
-  // OnImageChanged with an empty bitmap signifies a completed request.
-  observer_->OnImageChanged(request_id_, empty_bitmap);
 }
 
 void BitmapFetcherRequest::NotifyImageChanged(const SkBitmap& bitmap) {
   if (!bitmap.empty())
     observer_->OnImageChanged(request_id_, bitmap);
 }
 
 BitmapFetcherService::CacheEntry::CacheEntry() {
 }
 
@@ skipping 120 matching lines @@
   }
 
   if (!bitmap->isNull()) {
     CacheEntry* entry = new CacheEntry;
     entry->bitmap.reset(new SkBitmap(*bitmap));
     cache_.Put(fetcher->url(), entry);
   }
 
   RemoveFetcher(fetcher);
 }